CN105298924B - Compressor bionics stator blade and its implementation based on humpback flipper - Google Patents

Abstract

The compressor bionics stator blade and its implementation based on humpback flipper of a kind of aero-engine technology field, the bionics stator blade include three folded blade profiles of product successively, wherein：The a length of arithmetic progression of mean camber line of three blade profiles；The undaform curve for being shaped as mechanical periodicity of first blade profile and the leading edge portion of trilobal cross, the difference of described arithmetic progression is the wave amplitude of the waveform curve.The present invention changes Modeling Technology using local geometric, has certain wave amplitude of reduction resistance and the undaform curve of wavelength in stator blade leading edge application, the flow separation of stator blade suction surface is controlled, so as to improve blade aerodynamic performance.

Description

Bionic compressor vane based on humpback whale flipper and its realization method

technical field

The invention relates to a technology in the field of aero-engines, in particular to a bionic vane of a compressor based on a humpback whale flipper and a realization method thereof.

Background technique

Flow separation near blades is a common phenomenon in aeroengine axial-flow high-pressure compressors. However, serious flow separation will lead to channel blockage and a sharp increase in aerodynamic loss, and even cause the compressor to stall.

The methods of controlling flow separation in compressor design can be divided into two categories: active control and passive control. Compared with active control technology, passive control technology has the advantages of simple structure and easy implementation. Among many passive control technologies, blade modification is an effective flow control technology, including: curved blade shape, local geometric modification shape, etc. It has the advantages of easy implementation and high reliability, and has been widely used in many engines. . However, the current blade modification still has the defect of insufficient power.

After searching the existing technology, it is found that the Chinese patent document number CN104612758A, published (announcement) date 2015.5.13, discloses a low-loss low-pressure turbine blade, which is characterized in that the original low-pressure turbine blade is divided along the blade height direction The blade root area, the blade tip area and the two-dimensional flow area are formed. At the same time, wave-shaped cutting is performed on the leading edge to form multiple serrations on the leading edge, and 3% of the axial chord length of the original low-pressure turbine blade is cut. Lengthening, to make up for the decline in the working ability of the blade shape after cutting, the extension is carried out in the direction of the tangent of the arc in the front edge of the arc in the blade. This technology only considers the loss problem in the low-pressure turbine environment, and does not elaborate on the situation in the compressor vane environment, and the zigzag structure of the technology at the leading edge of the blade will cause discontinuity in the curvature of the crest and trough. bring about additional local losses.

The tissues and organs of many organisms in nature often have special structures. With the help of the analysis of these structures and their functions, many of our technical problems can be solved. Marine biologists' work on the morphology of the humpback's flippers has shown that the humpback's flippers are capable of high maneuverability and powerful hydrodynamic properties, which are largely attributable to the scalloped shape of the leading edge Nodular protrusions.

Contents of the invention

The present invention aims at the above-mentioned deficiencies existing in the prior art, and combines bionics principles and passive control technology in blade modification, proposes a compressor bionics stator blade based on humpback whale flippers and its implementation method, which can realize Effective separation control improves aero-engine efficiency.

The present invention is achieved through the following technical solutions:

The invention relates to a compressor bionic static vane based on the humpback whale flipper, which comprises three leaf shapes stacked in sequence, wherein the middle arc lengths of the three leaf shapes are arithmetic progressions.

Among the three airfoils, the shapes of the leading edge portions of the first airfoil and the third airfoil are periodically changing wavy curves, and the difference of the arithmetic sequence is the amplitude of the wavy curves.

The range of amplitude A of the wave-shaped curve is 1%L≤A≤3%L, and the range of wavelength W is 5%c≤W≤25%c, wherein: L is the prototype static blade, that is, the center of the second blade type arc length; c is the chord length of the prototype static blade.

The wavy curve is specifically: a cubic spline curve composed of a cubic spline function, the cubic spline curve is given a division a=x ₀ <x ₁ <...<x _n on the interval [a, b] _-1 <x _n ＝b, the function F(x) on this interval satisfies:

1) F(x) in each small interval [x _i-1 , x _i ] (i=1, 2, ..., n) is a cubic polynomial function;

2) Establish F ^(k) ( _xi -0)=F ^(k) ( _xi +0) at the node F(x), k=0, 1, 2, that is, the cubic polynomial function on the small interval is at the node The second-order continuity at x _i ;

3) The node ( _xi , y _i ) satisfies the condition y _i =F( _xi ) (i=0, 1, 2, . . . , n).

The stacking is preferably radial stacking, more preferably trailing edge stacking.

The present invention relates to a method for realizing the above-mentioned bionic vane of the compressor, comprising the following steps:

1) Step 1: Carry out parametric modeling on the compressor prototype stator blade, and adopt the modeling method of mid-arc and thickness distribution for blades with different blade height sections to ensure that the leading edge points and trailing edge points are all on the mid-arc line ;

2) Step 2, modeling the high leading edge of the prototype vane, so that the leading edge part forms a periodically changing wave-shaped curve, wherein: the amplitude of the periodically changing wave-shaped curve is A, and the wavelength is W; the periodic change The wavy curve is a cubic spline curve composed of cubic spline functions;

3) A modified airfoil with a mid-arc length of L+A is obtained by extending the mid-arc of the near-leading edge section, and a modified airfoil with a mid-arc length of L-A is obtained by shortening the mid-arc of the near-leading-edge section; Shape the leading edge of the modified airfoil according to the mid-arc length of the modified airfoil, so that the leading edge of the modified airfoil forms a wave-shaped curve that changes periodically, and the ratio of the amplitude and wavelength to the mid-arc length The same ratio as the prototype vane amplitude and wavelength to the arc length in the prototype vane;

4) According to different wavelengths, the prototype airfoil and the two modified airfoils are radially stacked in the way of trailing edge stacking.

technical effect

Compared with the prior art, according to the characteristics of the nodular protrusion structure at the leading edge of the humpback whale flipper, the present invention combines the local geometric modification modeling technology to apply a wave-shaped nodular protrusion with a certain amplitude and wavelength on the leading edge of the vane. Utilizing the characteristics of low resistance of the wavy knot-like protrusions, the flow separation of the suction surface of the stator blade is controlled, thereby improving the aerodynamic performance of the blade.

Description of drawings

Fig. 1 is the schematic diagram of the prototype stator blade of the present invention;

Fig. 2 is the wavy curve schematic diagram of periodic change among the present invention;

Fig. 3 is the schematic diagram of the bionics stator blade of the present invention;

Fig. 4 is a schematic diagram of a vertical projection plane of the present invention;

In the figure: radial direction X, middle arc direction S, pitch direction Y, axial direction Z, leading edge LE, trailing edge TE.

detailed description

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

Example 1

The design parameters of the stator vane part of the prototype compressor in this embodiment are: the chord length of the prototype vane vane is 51 mm, the blade height is 51 mm, the installation angle is 16.9°, the aspect ratio is 1, and the mid-arc length is 53.2 mm.

This embodiment is realized through the following steps:

1) As shown in Figure 1, the parametric modeling of the compressor prototype vane is carried out: as shown in Figure 4, the airfoils with different blade height sections adopt the shape of the middle arc and the thickness distribution to ensure that the leading edge points and The trailing edge points are all on the middle arc, where: the chord length of the prototype stationary blade c=51mm, the middle arc length L=53.2mm, and the full blade height H=51mm;

2) As shown in Figure 2, shape the high leading edge of the prototype stator blade so that a periodically changing wavy curve is formed at the leading edge, wherein the amplitude of the periodically changing wavy curve is preferably 3% L, and the wavelength is W It is preferably 20% c, that is, the amplitude is 1.596mm, and the wavelength is 10.2mm; the wavy curve of the periodic change is a cubic spline curve formed by a cubic spline function, which ensures the second-order continuity of the curve;

3) A modified airfoil with a mid-arc length of 103%L is obtained by extending the mid-arc of the near-leading edge section, and a modified airfoil with a mid-arc length of 97%L is obtained by shortening the mid-arc of the near-leading-edge section, That is, the mid-arc lengths of the two modified airfoils are 57.796mm and 51.604mm respectively; according to the mid-arc length of the modified airfoil, the leading edge of the modified airfoil is shaped so that the leading edge of the modified airfoil Form a wave-shaped curve that changes periodically. The modified blade shape with a middle arc length of 57.796mm has an amplitude of 1.734mm and a wavelength of 10.2mm, and the modified blade shape with a middle arc length of 51.604mm has an amplitude of 1.548mm and a wavelength of 10.2mm. mm;

4) According to different wavelengths, the prototype airfoil and the two modified airfoils are radially stacked in the way of trailing edge stacking.

As shown in Fig. 3, the compressor bionic stator blade obtained according to the above method.

The cubic spline curve is given a division a=x ₀ <x ₁ <...<x _n-1 <x _n =b on the interval [a, b], and the function F(x) on this interval satisfies the following condition:

(1) F(x) in each small interval [ _xi-1 , x _i ] (i=1, 2, ..., n) is a cubic polynomial function;

(2) Establish F ^(k) ( _xi -0)=F ^(k) ( _xi +0) at the node F(x), k=0, 1, 2, that is, the cubic polynomial function on the cell interval is Second-order continuity at node x _i ;

(3) The node ( _xi , y _i ) satisfies the condition y _i =F( _xi ) (i=0, 1, 2, . . . , n).

As far as the incoming flow at +8° angle of attack is concerned, the compressor bionic vane of the present invention is compared with the prototype vane: the separation flow area of the suction surface of the vane is reduced, and the total pressure loss coefficient is reduced by 4%.

Claims (5)

1. A method for realizing a bionic compressor vane based on a humpback whale flipper, wherein the bionic vane of a compressor comprises three leaf shapes stacked in sequence, wherein: three leaves The arc length of the type is an arithmetic sequence; Among the three airfoils, the shapes of the leading edge parts of the first airfoil and the third airfoil are periodically changing wave-shaped curves, and the difference of the arithmetic sequence is the amplitude of the wave-shaped curves; Described method specifically comprises the following steps: 1) Step 1: Carry out parametric modeling on the compressor prototype stator blade, and adopt the modeling method of mid-arc and thickness distribution for blades with different blade height sections to ensure that the leading edge points and trailing edge points are all on the mid-arc line ; 2) Step 2, modeling the high leading edge of the prototype vane, so that the leading edge part forms a periodically changing wave-shaped curve, wherein: the amplitude of the periodically changing wave-shaped curve is A, and the wavelength is W; the periodic change The wavy curve is a cubic spline curve composed of cubic spline functions; 3) A modified airfoil with a mid-arc length of L+A is obtained by extending the mid-arc of the near-leading edge section, and a modified airfoil with a mid-arc length of L-A is obtained by shortening the mid-arc of the near-leading-edge section; The mid-arc length of the modified airfoil shapes the leading edge of the modified airfoil so that the leading edge of the modified airfoil forms a wave-shaped curve that changes periodically, and the ratio of the amplitude and wavelength to the mid-arc length is the same as that of the prototype The ratio of the vane amplitude and wavelength to the length of the arc of the prototype vane is the same, where: L is the vane of the prototype, that is, the length of the arc of the second blade type; 4) According to different wavelengths, the prototype airfoil and the two modified airfoils are radially stacked in the way of trailing edge stacking. 2. The method according to claim 1, characterized in that, the amplitude A range of the wave-shaped curve is 1%L≤A≤3%L, the wavelength W range is 5%c≤W≤25%c, Among them: c is the chord length of the prototype stator blade. 3. The method according to claim 1 or 2, wherein the wavy curve is specifically: a cubic spline curve formed by a cubic spline function, and the cubic spline curve is in the interval [a, b] Given a partition a=x ₀ <x ₁ <...<x _n-1 <x _n =b, the function F(x) on this interval satisfies: 1) F(x) in each small interval [x _i-1 , x _i ] (i=1, 2, ..., n) is a cubic polynomial function; 2) Establish F ^(k) ( _xi -0)=F ^(k) ( _xi +0) at the node F(x), k=0, 1, 2, that is, the cubic polynomial function on the small interval is at the node The second-order continuity at x _i ; 3) The node ( _xi , y _i ) satisfies the condition y _i =F( _xi ) (i=0, 1, 2, . . . , n). 4. The method according to claim 1, wherein said stacking is radial stacking. 5. The method according to claim 1, wherein the chord length c of the prototype stator blade is equal to the full blade height H.